Field of the Invention
The present invention relates to a tool changer equipped with covers to prevent intrusion of foreign matter into a turret.
Description of the Related Art
A tool changer which automatically changes a tool mounted on a spindle of a machine tool are used conventionally. Plural tools necessary for operations are set in advance on the tool changer, which is configured to automatically change the tool mounted on the spindle of the machine tool to a specified tool according to machining conditions.
Examples of a machine tool equipped with such an automatic tool changer adapted to automatically change the tool includes a machine tool equipped with a turret which in turn is equipped with plural grips adapted to grip tools. Such a machine tool is disclosed in Japanese Patent Application Laid-Open No. 2010-99766. The machine tool has a turret in which plural tools are mounted and changes the tool mounted on the spindle by indexing the turret, making it possible to change the tool precisely at high speed. However, the turret and the turret base are simply connected with each other with a space provided between the front side of the turret and the base, and consequently, there is fear that chips produced during machining or a cutting fluid might intrude inside the turret.
FIG. 3 shows an automatic tool changer 2 adapted to automatically change a tool 4 mounted on a spindle 3 of a machine tool 1, according to conventional art.
In the automatic tool changer 2, as shown in FIG. 3, the turret 6 is equipped with covers to prevent intrusion of chips and cutting fluid into the turret 6 when a workpiece is machined. The machine tool 1 includes a spindle 3 and a spindle motor 5 adapted to drive the spindle 3 and a tool 4 is mounted on a tip of the spindle 3. Also, the spindle 3 is connected with a Z-axis motor 11 via a Z-axis ball screw 10, and the spindle 3 can be driven upward and downward by the Z-axis motor 11. Furthermore, the turret 6 is provided as a member for use to change the tool 4.
The turret 6 is equipped with a front cover 61 and rear cover 62 to avoid impacts on structural members (not shown) inside the turret 6, where the front cover 61 plays a role in preventing intrusion of chips and cutting fluid through the front face of the turret 6 while the rear cover 62 plays a role in preventing intrusion of chips and cutting fluid through the rear face of the turret 6.
Thus, depending on the geometry of the rear cover 62, chips and cutting fluid may tend to gather on a top side (part A) of a cylindrical portion 64. Then, in changing the tool 4, the spindle 3 is driven upward and downward by the Z-axis motor 11. Here, as the spindle 3 is provided with a cam 7, when the spindle 3 is moved up and down, the turret 6 is caused to perform oscillating motion by a cam follower 8 configured to follow the cam 7. Consequently, there is fear that during the oscillating motion, the chips and cutting fluid gathered on the top side (part A) of the cylindrical portion 64 might intrude inside the turret 6 through a gap 65 between the front cover 61 and rear cover 62 as indicated by a path B and adversely affect the structural members inside the turret 6.